where x and y are the size in mm of your diplay, will corect the font sizes in X. Basically it forces X to use a different DPI for calculating font sizes than the default 75x75. The effects don't take effect until the Xserver is restarted and from within the KDE control center, antialiasing is disabled (it can be reenabled directly after. The state needs to be switched briefly to make the changes take effect).

This has a remarkable effect on my laptop which has a fixed res of 1400x1050 and attempting diff res's causes the system to freeze. The default res and fonts were too small and caused significant eye strain, but now, with the dpi set to 124x122, they are super clear.

This works regardless if you use the XFS or not. YMMV depending on display size and the res you normally run at but smaller displays running at high res(like laptop LCDs) can benefit greatly.

If you don't like the new look then simply removing the DisplaySize line mentioned above resorts to the previous setup.

You probably want to make sure that the ratio of width to height is 4:3, even if you measure it and it doesn't quite work out that way. Otherwise it'll probably think you have a monitor with a non-normal aspect ratio and set different DPIs for the two directions (which can cause trouble). Of course, you don't want to set a 4:3 aspect ratio if you have a 16:9 monitor or something.

Edit: I was sitting here wondering why pictures of pyramids were popping into my head, and I think I figured out why. If, like me, you don't have a ruler handy, or you don't feel like trying to measure a curved surface, you can use this formula:
Width = 4*X/5
Height = 3*X/5
Where X is the viewable area of your monitor measured diagonally (which can be found in your monitor's specs on the mfgs. web site or it's manual). On my 19" Sony, for example, it's 18.0". So my monitor is 14.4x10.8. Of course, don't forget to convert your units._________________"An empty head is not really empty; it is stuffed with rubbish. Hence the difficulty of forcing anything into an empty head."
-- Eric Hoffer

Here is the size for both a very old COMPAQ Presario 1525 screen (15" officially, I guess) and my laptop's screen. I was quite astonished that they had the same size! Of course, the values are slightly tuned so that the aspect ratio is precisely 4/3.

DisplaySize 260 195

Yep, that's 12.8" for ya! My laptop's screen is officially a 13" screen, so that's okay, but so much for the 15" of Compaq!

As you can see, we're quite far from the values which your monitors are supposed to have!

lars_msh: I suggest you use 320 240 (nice 4/3 value), this is what I use on mine. Also, note that there are not much more than 1200x900 physical "pixels" (let's say, groups of phosphor dots) on that screen (1260x940 if I remember correctly). I used to use a 1200x900@100Hz hand-made resolution, but have since switched to more standard values._________________killed by a fire ant, while helpless